Research On Driving Motor And Control System Of High Voltage Circuit Breaker Operating Mechanism

The high voltage circuit breaker plays an important role in equipment control and protection in the operation of the power grid.The core components include the arc extinguishing chamber,the contact and the operating mechanism.In order to reliably extinguish the arc,the operating mechanism is designed for breaking short circuit and large current.Commonly used hydraulic,pneumatic,spring and other operating mechanisms are pre-stored energy.When the control command is issued to the mechanism,the pre-stored energy can be released immediately to complete the switch-on operation,which has the characteristics of large output power,complex structure and uncontrollable movement process.In order to meet the development needs of intelligent power grid and improve the real-time control ability of circuit breakers in the process of movement,this paper adopts modern power electronics technology and communication technology,designs drive motor and control system to meet the requirement of breaking and closing of circuit breakers.Mainly carry out the following work:(1)The brushless direct current motor is taken as the research object to analyze the dynamic characteristics during the motor start up process.the mathematical model of the driving motor is established,and the relationship between the output electromagnetic torque of the motor and the winding voltage is calculated.The simulation model of the control system is established by Matlab.It is proved that the speed of the driving motor is related to the winding voltage,and the purpose of speed regulation of the motor can be achieved by adjusting the voltage.(2)Combining with the dynamic characteristics of 126 kV vacuum circuit breaker,the motion process of transmission mechanism and circuit breaker segmented to optimize the design,the open distance stage of the circuit breaker is segmented control,and the contact motion process of vacuum circuit breaker is dynamically analyzed.According to the requirements of the circuit breaker's motion characteristics,the parameters of the motor are designed and selected to determine the overall parameters of the motor.The designed permanent magnet brushless direct current motor was modeled and simulated in Ansoft,and the simulation results were analyzed.(3)The hardware control system of the motor operating mechanism is built,including energy storage detection unit,switching capacitor bank unit,rectifier inverter unit,signal acquisition unit,main processor unit,isolated drive unit,etc.Aiming at the hardware circuit of the operating mechanism,the corresponding program block diagram and programming are established,and the boost device of the switched capacitor bank is used to realize the double boost of the control device.The control device which combines hardware and software is assembled and debugged,and the whole control system of motor operating mechanism is completed.(4)The stability test of the motor operating mechanism of the vacuum circuit breaker and the opening and closing operation experiment under different operation modes were carried out.Through the analysis of the experimental results,it is found that increasing the storage voltage value of the energy storage capacitor can increase the moving speed of the dynamic contacts of the circuit breaker and reduce the opening and closing time of the circuit breaker.Compared with the conventional opening and closing characteristics experiment,the closing time of the switched capacitor group was reduced by 11.1ms,the closing speed was increased by 0.67m/s,the total opening time was reduced by 25.8ms,and the opening speed was increased by 1.67m/s,which proves the stability and rationality of the control device.